This invention relates to a cleaning arrangement for heat exchanger tubes.
It is known from the above-identified patents to connect elongated cleaning element capturing cages to both ends of the heat exchanger tubes. The cages are adapted to contain shuttlable cleaning elements, such as brushes. Fluid flowing in one direction through the tubes keeps the cleaning elements captured within their respective cage chambers, while the fluid discharges outwardly through slot-like openings in the cage walls. Upon reversal of fluid flow, the cleaning elements are forced out of their cages and through the tubes to the cages at the opposite tube ends to thereby perform a tube cleaning action.
Heretofore, the cages have all been of approximately the same length with the fluid flow openings in the cage walls being transversely aligned in the same plane.
It has been observed that, especially in high fluid pressure applications, the cleaning elements sometimes tended to be pushed laterally outwardly and partially or completely through the cage openings. Upon fluid flow reversal, the cleaning elements could then no longer perform their cleaning function.
The present invention is directed to solving the problem of undesirable lateral displacement of the tube cleaning elements, while reducing the pressure drop of the laterally flowing fluid in the heat exchanger chamber containing the cage-cleaning element assemblies.
In accordance with an aspect of the invention, a plurality of elongated tube cleaning element capturing cages of different lengths are mounted within the heat exchanger chamber. The cages are so constructed and positioned so that fluid discharging outwardly from the cages flows laterally in a plurality of transverse planular layers.
In accordance with another aspect of the invention, fluid discharging laterally through the openings of the shorter cages impinges against closed wall portions of the longer cages, with the openings of the longer cages being disposed axially beyond the openings of the shorter cages.
In accordance with a further aspect of the invention, the longer and shorter cages may be arranged in substantially alternating relationship. In the event that some longer or shorter cages are disposed directly adjacent each other, openings of adjacent similar length cages are disposed in generally facing relationship with imperforate portions of the adjacent similar length cage.